I predicted DS1 would come at exactly 38 weeks and that's what I planned for even though everybody tried to talk me out of it. I went into labor the day I was 38 weeks and he was born the morning of 38w1d.
DS2 was double-footling breech so they scheduled a c-section for 39w4d. I was SURE he would come earlier than that, but he was quite content to stay where he was. I had no signs of labor starting by the time they did the c-section.